UEFI... Do I need it? Prefer the old BIOS. (Aurora r4)

Okay, here's the deal... I'm about to do a complete re-installation of Windows 7 on my Aurora R4.  The R4 has the option to change from UEFI to Legacy... I'm assuming Legacy is good old-fashioned "BIOS". 

Why don't I like UEFI?  For a simple reason - I use pre-boot authentication and whole disk encryption.  Unfortunately, PGP (and Truecrypt) do not work on UEFI because of the way the booting process works.  The only thing that does work is Bitlocker, which I am finding to be not as secure - I do not have a TPM module, and I find myself leaving the authentication token in the port.  I know there are pros and cons to everything, but I prefer the old way.

So, if I changed over to Legacy, would I be able to reinstall Windows 7 and then use those programs?  Also, what would I be missing out on going from UEFI to BIOS?

If it helps, my hard drive is 2 gigs.  I don't know if that makes any difference.

Edit...  2tb, im livin in the past...